Multi-metallic composite carbon structure ozone catalyst, preparation method and application

Abstract

This invention discloses a multi-metal composite carbon structure ozone catalyst, its preparation method, and its application. The catalyst preparation method includes the following steps: S1: preparation of a glucose solution; S2: dissolving an organometallic salt in the glucose solution of S1; S3: adding γ-Al2O3 microspheres to the mixed solution of S2, impregnating and then drying; S4: transferring the dried solid from S3 to a tube furnace, pyrolyzing it under nitrogen protection, and obtaining the multi-metal composite carbon structure ozone catalyst after cooling and acid washing. This invention uses glucose as a carbon source, obtaining carbon materials through high-temperature calcination in the absence of oxygen. The structure formed with the metal salt includes metallic carbon (M-C), organic carbon (COOR), and graphitic carbon (C HOPG), which can enhance the solid-liquid-gas three-phase mass transfer in the ozone catalytic process, significantly improving the efficiency of ozone oxidation of pollutants.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a multi-metal composite carbon structure ozone catalyst, its preparation method, and its application. Background Technology

[0002] While advancements in science and technology and industrial development have brought convenience to people, they have also exacerbated environmental pollution. Water pollution, in particular, is a major concern, with the discharge and use of domestic sewage and industrial wastewater leading to water scarcity. Therefore, designing and developing suitable wastewater treatment processes to purify and reuse wastewater is an effective means of addressing water shortages. Industrial wastewater, due to its complex composition, high COD content, and the difficulty in degrading pollutants, presents a significant challenge in water treatment processes, necessitating an effective solution.

[0003] Advanced oxidation technologies (AOPs) oxidize and degrade recalcitrant pollutants by generating highly oxidizing reactive oxygen species (ROS), such as hydroxyl radicals and superoxide radicals. AOPs based on ozone catalytic oxidation offer advantages such as strong oxidizing power, wide applicability, online oxidant preparation, simple equipment, low operating costs, and no secondary pollution, thus finding widespread application in water treatment. However, the low efficiency of ozone in treating certain pollutants and oxidation intermediates, along with its low solubility in water, limits the application of ozone oxidation technology. To address this, technologies such as UV-ozone, ozone-hydrogen peroxide co-processing, and homogeneous catalytic ozone oxidation have been developed. While these technologies can improve ozone treatment efficiency, the addition of reagents and the introduction of UV light increase treatment costs and complicate the process equipment.

[0004] Heterogeneous ozone catalytic activation technology can catalyze the production of ROS from ozone without introducing secondary pollution. Its advantages, such as catalyst reuse and a simple process flow, make it promising for widespread application. However, existing ozone catalysts still suffer from low catalytic efficiency, limited mass transfer, and limited lifespan. Therefore, designing and synthesizing a stable and efficient heterogeneous ozone catalyst is of great significance for improving ozone catalytic oxidation efficiency, enhancing industrial wastewater treatment efficiency, and addressing water resource issues. Summary of the Invention

[0005] Based on the technical problems existing in the background technology, this invention proposes a multi-metal composite carbon structure ozone catalyst, its preparation method and application, which can significantly improve the efficiency of ozone oxidation of pollutants.

[0006] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0007] S1: Preparation of glucose solution;

[0008] S2: Dissolve the organometallic salt in the glucose solution of S1;

[0009] S3: Add γ-Al2O3 microspheres to the mixed solution of S2, impregnate and then dry;

[0010] S4: The solid after drying S3 is transferred to a tube furnace and pyrolyzed under nitrogen protection. After cooling and acid washing, a multi-metal composite carbon structure ozone catalyst is obtained.

[0011] Preferably, the concentration of the glucose solution in S1 is 0.5-1.2 mol / L.

[0012] Preferably, the molar mass ratio of glucose, metal salt and γ-Al2O3 is 0.1-0.3 mol: 0.5-2 g: 100 g.

[0013] Preferably, the organometallic salt is two or more of the following: iron salt, cobalt salt, copper salt, zinc salt, manganese salt, and nickel salt.

[0014] Preferably, the soaking time in S3 is 20-30 hours, and the drying temperature is 70-90°C.

[0015] Preferably, in S4, the pyrolysis temperature is increased to 500-800℃ at a rate of 5-8℃ / min, and pyrolysis is carried out at this temperature for 3-6 hours.

[0016] The multi-metal composite carbon structure ozone catalyst prepared by the method proposed in this invention.

[0017] The application of the above-mentioned multi-metal composite carbon structure ozone catalyst proposed in this invention in water treatment.

[0018] Beneficial technical effects of the present invention:

[0019] This invention uses glucose as a carbon source and obtains carbon materials by high-temperature calcination in the absence of oxygen. The structure formed with metal salts includes metallic carbon (MC), organic carbon (COOR), and graphitic carbon (C HOPG), which can enhance the solid-liquid-gas three-phase mass transfer in the ozone catalysis process and significantly improve the efficiency of ozone oxidation of pollutants. This invention also utilizes the high reactivity and intermetallic interactions of low-cost transition metals to enhance the intrinsic activity of ozone catalysis. Attached Figure Description

[0020] Figure 1 (a) Photograph of the catalyst of Example 1 proposed in this invention, and (b) SEM image of the catalyst after grinding in Example 1;

[0021] Figure 2 EDS-Mapping of the catalyst in Example 1 of this invention;

[0022] Figure 3XPS images of the catalyst in Example 1 of this invention: (a) Cu 2p, (b) Fe 2p, (c) Co 2p, (d) C1s;

[0023] Figure 4 BET results of the catalyst in Example 1 of this invention;

[0024] Figure 5 The COD degradation curves of phenol using different metal catalysts proposed in this invention are shown below.

[0025] Figure 6 The figures show the COD degradation curves in the secondary sedimentation tank for catalysts with different metal ratios proposed in this invention. Detailed Implementation

[0026] The present invention will be further explained below with reference to specific embodiments.

[0027] Example 1

[0028] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0029] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0030] (2) Add 0.3g of ferric ammonium citrate, 0.2g of cobalt acetate and 0.1g of copper acetate to the above solution respectively, and stir to dissolve.

[0031] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0032] (4) The solid obtained in step (3) was transferred to a tube furnace and heated to 600℃ at a heating rate of 5℃ / min under nitrogen protection for 4 hours. After cooling to room temperature, surface impurities were washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoCu(3-2-1)-CA catalyst. Figure 1 a).

[0033] The catalyst obtained in this example was ground and then subjected to surface electron microscopy (SEM) imaging. The resulting morphology images are shown below. Figure 1 b. The figure clearly shows the shape and microstructure of the material. Energy dispersive spectroscopy (EDS-Mapping) was performed on the material, as shown below. Figure 2 As shown, Fe, Co, Cu, and C are uniformly distributed in the material. X-ray photoelectron spectroscopy was then used to characterize the catalyst, determining its elemental composition and valence states. Figure 3As can be seen, Fe, Co, and Cu are all present in the material. Cu mainly exists in the +1 and +2 oxidation states, Fe mainly exists in the +2 and +3 oxidation states, and Co mainly exists in the +2 oxidation state. Meanwhile, C mainly exists in three forms: heated graphite carbon (CHOPG), which has the highest content, followed by metal-C MC, and a small amount of organic carbon (COOR) is also present. Based on this, the solid-liquid-gas three-phase mass transfer in the ozone catalytic process is enhanced, significantly improving the efficiency of ozone oxidation of pollutants. The specific surface area of ​​the material was determined by BET surface area testing, such as... Figure 4 Due to the introduction of carbon materials, the specific surface area is significantly increased to approximately 190 m². 2 / g, this large specific surface area is beneficial to the solid-liquid-gas mass transfer of heterogeneous ozone catalytic systems.

[0034] Example 2

[0035] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0036] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0037] (2) Add 0.2g of ferric ammonium citrate, 0.2g of cobalt acetate and 0.2g of copper acetate to the above solution respectively, and stir to dissolve.

[0038] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0039] (4) The solid obtained in step (3) is transferred to a tube furnace and heated to 600°C at a heating rate of 8°C / min under nitrogen protection, and pyrolyzed for 5 h. After cooling to room temperature, surface impurities are washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoCu(2-2-2)-CA, denoted as FeCoCu-CA.

[0040] Example 3

[0041] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0042] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0043] (2) Add 0.3g of ferric ammonium citrate, 0.1g of cobalt acetate and 0.2g of copper acetate to the above solution and stir to dissolve.

[0044] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0045] (4) The solid obtained in step (3) is transferred to a tube furnace and heated to 600°C at a heating rate of 8°C / min under nitrogen protection for 5 hours. After cooling to room temperature, surface impurities are washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoCu(3-1-2)-CA catalyst.

[0046] Example 4

[0047] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0048] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0049] (2) Add 0.2g of ferric ammonium citrate, 0.2g of cobalt acetate and 0.2g of nickel acetate to the above solution respectively, and stir to dissolve.

[0050] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0051] (4) The solid obtained in step (3) is transferred to a tube furnace and heated to 600°C at a heating rate of 8°C / min under nitrogen protection for 5 hours. After cooling to room temperature, surface impurities are washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoNi(2-2-2)-CA, denoted as FeCoNi-CA.

[0052] Example 5

[0053] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0054] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0055] (2) Add 0.2g of ferric ammonium citrate, 0.2g of cobalt acetate and 0.2g of zinc acetate to the above solution respectively, and stir to dissolve.

[0056] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0057] (4) The solid obtained in step (3) is transferred to a tube furnace and heated to 600°C at a heating rate of 8°C / min under nitrogen protection for 5 hours. After cooling to room temperature, surface impurities are washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoZn(2-2-2)-CA, denoted as FeCoZn-CA.

[0058] Example 6

[0059] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0060] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0061] (2) Add 0.2g of ferric ammonium citrate, 0.2g of cobalt acetate and 0.2g of manganese acetate to the above solution respectively, and stir to dissolve.

[0062] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0063] (4) The solid obtained in step (3) is transferred to a tube furnace and heated to 600°C at a heating rate of 8°C / min under nitrogen protection for 5 hours. After cooling to room temperature, surface impurities are washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoMn(2-2-2)-CA, denoted as FeCoMn-CA.

[0064] Example 7

[0065] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0066] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0067] (2) Add 0.3g of ferric ammonium citrate, 0.2g of cobalt acetate and 0.1g of copper acetate to the above solution respectively, and stir to dissolve.

[0068] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0069] (4) The solid obtained in step (3) is transferred to a tube furnace and heated to 600°C at a heating rate of 8°C / min under nitrogen protection for 5 hours. After cooling to room temperature, surface impurities are washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoCu(3-2-2)-CA catalyst.

[0070] Example 8

[0071] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0072] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0073] (2) Add 0.2g of ferric ammonium citrate, 0.2g of cobalt acetate and 0.2g of nickel acetate to the above solution respectively, and stir to dissolve.

[0074] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0075] (4) The solid obtained in step (3) is transferred to a tube furnace and heated to 600°C at a heating rate of 8°C / min under nitrogen protection for 5 hours. After cooling to room temperature, surface impurities are washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoNi(2-2-2)-CA catalyst.

[0076] Example 9

[0077] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0078] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0079] (2) Add 0.3g of ferric ammonium citrate, 0.2g of cobalt acetate and 0.1g of nickel acetate to the above solution and stir to dissolve.

[0080] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0081] (4) The solid obtained in step (3) is transferred to a tube furnace and heated to 600°C at a heating rate of 8°C / min under nitrogen protection for 5 hours. After cooling to room temperature, surface impurities are washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoNi(3-2-1)-CA catalyst.

[0082] Example 10

[0083] The preparation method of the multi-metal composite carbon structure ozone catalyst proposed in this invention includes the following steps:

[0084] (1) Add 100 mL of deionized water to a 250 mL beaker, add 0.08 mol of glucose, and stir to dissolve.

[0085] (2) Add 0.3g of ferric ammonium citrate, 0.1g of cobalt acetate and 0.2g of copper acetate to the above solution and stir to dissolve.

[0086] (3) Add 40g of γ-Al2O3 microspheres to the solution obtained in step (2), soak for 24h, and then transfer to an oven to dry at 80℃.

[0087] (4) The solid obtained in step (3) is transferred to a tube furnace and heated to 600°C at a heating rate of 8°C / min under nitrogen protection for 5 hours. After cooling to room temperature, surface impurities are washed away with 0.1 mmol / L sulfuric acid to obtain the catalyst FeCoNi(3-1-2)-CA catalyst.

[0088] Application Example 1

[0089] The COD removal efficiency of the catalysts prepared in Examples 2 and 4-6 was evaluated using phenol solution as a model pollutant. The specific methods and steps are as follows:

[0090] (1) Prepare a phenol solution with a COD of about 120 mg / L by adding 50 mg of phenol to 1 L of water and stirring to dissolve it. The COD is about 120 mg / L and the pH is 6.8.

[0091] (2) Pour 150 mL of the solution from step (1) into a beaker, without adding the catalyst, and add 5 g of the carrier catalyst from Examples 2 and Comparative Examples 1-3. Use pure oxygen as the oxygen source to generate ozone using an ozone generator. Measure and control the ozone concentration to 30 mg / L using an ozone concentration meter, and control the ozone flow rate to 100 mL / min using a flow meter.

[0092] (3) The mixed phenol wastewater catalyst solution was mechanically stirred at 20℃ and 500rpm for 40min, and 3mL samples were taken at regular intervals.

[0093] (4) The COD value of the solution was tested by rapid digestion-potassium dichromate colorimetric method. After the sample in step (3) was filtered through a 0.22 μm filter, 2 mL of the sample was added to the pre-prepared digestion solution and digested at 150 °C for 30 min. The COD value was determined by colorimetric method.

[0094] The obtained COD degradation curve is as follows Figure 5 As shown in the figure, FeCoCu-CA exhibits the best catalytic effect in the ozone degradation of COD. FeCoNi-CA also shows good results.

[0095] Application Example 2

[0096] The effluent from the secondary sedimentation tank of the industrial park was selected as the target wastewater. The COD removal efficiency of catalysts with different metal ratios (Examples 2, 3, and 7-10) was tested. The specific methods and steps are as follows:

[0097] (1) The initial COD of the secondary sedimentation tank effluent was tested by rapid digestion method and found to be about 130 mg / L. 150 mL of water sample was poured into a beaker without adding any catalyst and without adding 5 g of the carrier catalyst from Example 4 and Comparative Examples 4-8.

[0098] (2) Pure oxygen is used as the oxygen source, and ozone is generated using an ozone generator. The ozone concentration is measured and controlled at 30 mg / L by an ozone concentration meter, and the ozone flow rate is controlled at 100 ml / min by a flow meter.

[0099] (3) The mixed wastewater catalyst solution was mechanically stirred at 20℃ and 500rpm for 40min, and 3mL samples were taken at regular intervals.

[0100] (4) The COD value of the solution was tested by rapid digestion-potassium dichromate colorimetric method. After the sample in step (3) was filtered through a 0.22 μm filter, 2 mL of the sample was added to the pre-prepared digestion solution and digested at 150 °C for 30 min. The COD value was determined by colorimetric method.

[0101] The final COD degradation curve of the secondary sedimentation tank effluent is shown in the figure. Figure 6 As shown in the figure, the COD degradation efficiency of FeCoCu-CA is significantly higher than that of FeCoNi. Comparisons of different proportions of Fe, Co, and Cu catalysts show little difference, with FeCoCu(3-2-1)-CA exhibiting the best performance.

Claims

1. The application of a multi-metal composite carbon structure ozone catalyst in water treatment, characterized in that, The preparation steps of the multi-metal composite carbon structure ozone catalyst are as follows: S1: Preparation of glucose solution; S2: Dissolve the organometallic salt in the glucose solution of S1; S3: Add γ-Al2O3 microspheres to the mixed solution of S2, impregnate and then dry; S4: The solid after drying S3 is transferred to a tube furnace and heated for pyrolysis under nitrogen protection. After cooling and acid washing, a multi-metal composite carbon structure ozone catalyst is obtained. The organometallic salt is a first metal salt, a second metal salt, and a third metal salt, wherein the first metal salt is an iron salt, the second metal salt is a cobalt salt, and the third metal salt is one of a copper salt, a zinc salt, a manganese salt, and a nickel salt.

2. The application of the multi-metal composite carbon structure ozone catalyst according to claim 1 in water treatment, characterized in that, The concentration of glucose solution in S1 is 0.5-1.2 mol / L.

3. The application of the multi-metal composite carbon structure ozone catalyst according to claim 1 in water treatment, characterized in that, The soaking time in S3 is 20-30 hours, and the drying temperature is 70-90℃.

4. The application of the multi-metal composite carbon structure ozone catalyst according to claim 1 in water treatment, characterized in that, In S4, the temperature is increased to 500-800℃ at a rate of 5-8℃ / min, and then pyrolyzed at this temperature for 3-6 hours.

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